Device for transporting sheet-like articles

ABSTRACT

A device for transporting sheetlike material is proposed wherein the material to be conveyed is always held between a conveyer belt ( 1 ) and a guide means ( 20 ) each lying against one of the opposite sides of the material ( 23 ). In order to maintain a reliable transport function even with fluctuating sheet thickness, it is provided that the run of the conveyer belt facing the material ( 23 ) is loaded elastically in the direction of the material ( 23 ) by pressure elements ( 14, 16 ).

This invention relates to a device for transporting sheetlike materialbetween a conveyer belt and a guide means each lying against one of thetwo opposite sides of the material. Such devices are used in particularin paper conveying technology for example in printing machines, copiers,document processing machines and the like as well as in bank noteprocessing machines.

In the field of bank note transport it is known for example from DE 4302 827 A1 to transport bank notes between two transport belts movingequally fast and in the same direction. This transport method firstlyinvolves an elaborate and high-maintenance belt guiding system andregularly requires a great number of belt deflection points to transfersufficiently strong clamping power to the bank notes in order to conveythem in frictional engagement. To improve adhesion between thecirculating conveyer belts, DE 43 02 827 A1 proposes disposing means forcausing magnetic and/or electromagnetic forces. Such an arrangementquite obviously involves considerable effort and energy consumption andmoreover very quickly leads to problems of electromagnetic interference.Furthermore, one must also expect problems with the sensors usedtherein, in particular when used in bank note testing devices.

It is known from DE 28 57 883 C2 to convey bank notes between atransport belt and a fixed plate. Such a device has in particular thedisadvantage of tending to crinkle or jam the bank notes due to theone-sidedly applied high friction on the stationary wall.

A further problem occurring with conveyance by transport belts is theundefined clamping power the belt exerts on the bank notes to beconveyed in particular when bank notes of varying thickness are conveyedat short distances one behind the other. For example, if a thin banknote is located between two clearly thicker bank notes regarded in thetransport direction, a much lower frictional force is transferred tothis thinner bank note than to the two adjacent thicker bank notes.

For conveying sheet material it is also known from DE 29 14 969 A1 totransport the sheet material between a row of firmly mounted rollers anda further row of spring loaded rollers. Such an arrangement has thedisadvantage that the sheet material is unguided on both sides in thearea between two pairs of rollers so that crinkling or jamming caneasily occur.

The invention is therefore based on the problem of providing a devicefor transporting sheetlike material which guarantees a reliabletransport function even at high conveying speeds and with fluctuatingsheet thickness while being of simple structure and easy to maintain.

This problem is solved by a device according to claim 1.

The inventive solution is characterized in particular in that thesheetlike material is guided areally by the conveyer belt on the onehand, while the latter always ensures sufficient pressing force betweensheet material and conveyer belt by reason of the elastic action of thepressure elements.

It is advantageous with respect to wear and energy consumption if thepressure elements are formed as pivotally mounted rollers. It isparticularly suitable to use rolling bearings, which require littlemaintenance and are also especially cost-effective being standard parts.

For guidance and elastic bias of the pressure elements it isparticularly suitable to use leaf springs since they can perform bothfunctions with minimal effort and fitting space.

A preferred embodiment of the invention provides that the guide means isa roller train with pivotally mounted rollers. In particular if verygreat fluctuations in the sheet thickness of the transport material areto be expected, it is advantageous if the roller train consists ofrollers elastically acted upon in the direction of the conveyer belt.This permits part of the fluctuation in thickness of the sheet materialto be compensated by the motion of the pressure elements and theremaining part by the displacement of the guide means.

The pressure elements and the rollers of the roller train are preferablydisposed opposite each other in pairs. Especially good guidance of thetransport material is obtained if the roller train has cylindricalrollers since this results in linear clamping action on the transportmaterial, thereby reliably maintaining the given transport direction.

An embodiment of the invention which is particularly easy to maintainand to operate provides that the conveyer belt and guide means, on theone hand, and the pressure elements, on the other hand, are eachdisposed in a portion of a hinged frame.

It has a supporting effect on transport safety if the device has atransport channel into which both the conveyer belt and the guide meansprotrude. Said transport channel preferably covers the maximum sheetformat to be conveyed and ensures that disturbing influences are keptaway from the transport path, especially in the area of the side edgesof the sheets where there is a danger of dog ears forming.

Further advantageous features and the structure and function of theinvention will result from the following description of an embodimentwith reference to the drawing, in which:

FIG. 1 shows a side view of the transport device,

FIG. 2 shows an enlarged detail of FIG. 1,

FIG. 3 shows a front view of the transport device in the direction ofthe longitudinal axis of the conveyer belt, and

FIG. 4 shows a view of the transport device with a swung-open transportchannel.

FIG. 1 shows a side view of the transport path of a bank note processingmachine. Particularly such applications require a high standard ofsafety and reliability, especially since access to the transportmaterial itself must always be controlled due to the value of saidmaterial. Moreover, such applications involve fluctuations in thequality and also thickness of the material to be transported, resultingin extremely difficult conditions for a reliable mode of transport.

FIG. 1 shows elastic conveyer belt 1 guided around deflection rollers 2to 6 and around drive roller 7 and tension roller 8. Tension roller 8 ismounted so as to be vertically displaceable permitting the tension inconveyer belt 1 to be adjusted by corresponding displacement. Driveroller 7 is connected with a driving motor not shown. Horizontallyextending transport channel 9 is formed by two parallel walls 10 and 11.Transport channel 9 has a downward pointing arc-shaped bend betweendeflection rollers 2 and 3. The radius of this arc corresponds to theradius of deflection roller 2. Conveyer belt 1 extends in an S shapebetween deflection roller 2 acting upon the outer side of conveyer belt1 and deflection roller 3 acting upon the inner side of the belt.

From this arc-shaped portion the bank notes to be transported aresupplied to the transport device. The sense of rotation of conveyer belt1 is indicated by arrow 12. The lower run of conveyer belt 1 extendingbetween deflection roller 2 and drive roller 7 is located approximatelyin the middle between channel walls 10 and 11. Channel wall 10 islocated within the area run around by transport belt 1 while channelwall 11 is located below the lower run of the belt.

A plurality of pairs of threaded bushes 13 a are pressed into channelwall 10 on the side facing away from conveyer belt 1, as evident inparticular from FIG. 2, each pair clamping by means of inserted screws13 leaf spring 14 whose portions 15 facing away from supporting bolts 13are fork-shaped. Portions 15 encompass rolling bearings 16 along thefaces thereof lying biased from above on axles 17 carrying rollingbearings 16 and being connected with axle 17 by means of welding spot 18laterally of rolling bearing 16. Rolling bearings 16 protrude partlythrough corresponding window-like openings 19 of the channel wall.Window-like openings 19 provided for rolling bearings 16 and theguidance of axles 17 by fork-shaped portions 15 of leaf springs 14 canbe readily recognized in the view according to FIG. 4.

Disposed opposite rolling bearings 16 on the other side of conveyer belt1 are rolling bearings 20 guided by means of a cantilever support inmounting strip 21 extending parallel to conveyer belt 1 and connectedwith channel wall 11 so as to form a right angle.

As shown in FIG. 4, rolling bearings 20 are screwed to mounting strip 21by means of screw 22 in each case. Rolling bearings 20 also protrudeinto transport channel 9 through accordingly disposed window-likerecesses in channel wall 11 so that conveyer belt 1 can run thereon.

Rolling bearings 16 and 20 each have a cylindrical form so as to form anip line between them and conveyer belt I and the sheet material to beconveyed. This permits the conveyed sheet material to be guidedespecially reliably and prevents skew. In order to exclude externalinfluences on transport of sheet material 23, the width of the transportchannel is dimensioned such that the largest sheet format to betransported can be received completely by transport channel 9. Thedistance between individual pairs of rolling bearings 16 and 20 in thetransport direction is dimensioned such that the transport material isalways acted upon by at least two pairs of rolling bearings 16 and 20even with the smallest sheet format to be transported. This is clearlyrecognizable in FIG. 2 on bank note 23 located in the transport pathwith leading edge 24 and trailing edge 25.

When a sheet is supplied to the transport device via the arc-shapedportion of transport channel 9 it is grasped by conveyer belt 1 anddeflection roller 2, deflected by 90° in the arc and transported to theright according to FIG. 1. The first action upon or contacting of thesheet by conveyer belt 1 takes place in an area where the conveyer beltextends in an arc shape with the inner side of the arc compressed inthis phase. This contact surface is aligned straight in the transportdirection and the compression thus reduced in the further course ofconveyance. Since the trailing end of the sheet is still located inclamped engagement between conveyer belt 1 and deflection roller 2during the straight alignment of the conveyer belt and the sheet, atension is transferred to the sheet thereby stretching or straighteningit. During transport through transport channel 9 it comes successivelyinto linear clamping with particular rolling bearings 20 and viaconveyor belt 1 with biased rolling bearings 16. This guaranteesdirectional stability. During transport the sheet material thus alwayslies areally against traveling conveyer belt 1 with one side andlinearly against individual rolling bearings 20 successively.

Approximately in the middle of the transport channel there is sheetdiverter 26 to permit sheet material to be transferred out of transportchannel 9. The elastic action on conveyer belt 1 by biased rollingbearings 16 directly compensates differences in thickness of thematerial to be conveyed at each individual nip between opposite rollingbearings 16 and 20 so that reliable conveyance is given even when sheetsof very different thickness are to be transported very close behind eachother. In particular this prevents limp sheets from buckling or curling.

As shown in FIGS. 3 and 4, transport channel 9 can be opened very easilyfor purposes of maintenance, inspection or to eliminate jams, providingvery good access to the whole transport path and all elements involvedin conveyance. For this purpose upper channel wall 10 carrying rollingbearings 16 is pivotally attached to the basic frame 31 by joint 30,while lower channel wall 11 and the axles of deflection, drive andtension rollers 2 to 8 are connected firmly with the basic frame 31.

Upper channel wall 10 can be swiveled around joint 30 out of the homeposition shown in FIG. 3 after locking element 32 is undone, therebyreleasing transport channel 9.

Any sheet material 23 still located in transport channel 9 is now heldbetween conveyer belt 1 and at least two rolling bearings 20 withoutaction by biased rolling bearings 16.

What is claimed is:
 1. An apparatus having a basic frame fortransporting sheetlike material (23) between a conveyer belt (1) and aguide device supported by a lower portion of said basic frame (20) eachpositioned and configured along one of two opposite sides of thematerial (23), wherein the run of the conveyor belt (1) facing thematerial to be conveyed (23) is loaded elastically in the direction ofthe material (23) by pressure elements (14, 16) carried by an upperframe portion pivotally attached to said basic frame.
 2. The apparatusaccording to claim 1, wherein the pressure elements are formed aspivotally mounted rollers (16).
 3. The apparatus according to claim 1wherein the pressure elements are rolling bearings (16).
 4. Theapparatus according to claim 1 wherein the pressure elements are guidedand biased by means of leaf springs (14).
 5. The apparatus according toclaim 1 wherein the guide device is a roller train (20).
 6. Theapparatus according to claim 5 wherein the roller train (20) includesrollers elastically acted upon in the direction of the conveyor belt(1).
 7. The apparatus according to claim 6 wherein the pressure elements(14, 16) and the rollers of the ball train (20) are positioned oppositeeach other in pairs.
 8. The apparatus according to claim 5 wherein theroller train includes cylindrical rollers (20).
 9. The apparatusaccording to claim 1 wherein the device includes a transport channel (9)into which both the conveyor belt (1) and the guide device (20) protrudetherein.
 10. The apparatus according to claim 1 further comprising atransport channel including an upper channel wall and a lower channelwall, said upper channel wall forming a portion of said upper frameportion and said lower channel wall forming a portion of said lowerframe portion, wherein axles of rollers driving and guiding saidconveyor belt are connected to basic frame.